Characteristics of continental oil shale and oil shale resources

Petroleum & Basin Analysis InstituteJilin University

15/10/2008

Characteristics of continental oil shale and oil shale resources in China

Zhaojun Liu, Qingshui Dong, Qingtao Meng

Jilin University

Characteristics of continental oil shale

Genetic types of continental oil shale

Oil shale resources in China


Mineral characteristic

China's continental oil shale is mainly mudstone or shale, and is composed of terrestrial clastic material. Mineral composition is quartz, feldspar and clay minerals. Among clay minerals, the content of kaolinite is high. Compared with marine oil shale, the content of carbonate is higher.


Relatively content(%) Quartz Feldspar Kaolinte Montm-

orilloriteMixed mineral Illite Carbo-

nate

Dalianhe 33 3 57 3 4

11

5

8

Maoming 31 7 46 3 9 4

Estonia (marine) 9 6.8 14 56.1

Huadian 14 2 2 57 22

Nongàn 50 20 1 12 3

Luozigou 51 34 6 4

Fushun 55 13 13 8 16

Organic geochemical characteristics

1. Abundance of organic matterThe content of organic carbon in China's oil shale is

between 7.48% and 38.02%, the average is 21.46%, and mainly concentrated in the range between 10% and 30%.

Histogram of organic carbon distribution of oil shale

Num

bers

of s

ampl

es TOC (%)


2. The types of organic matter

The types of organic matter of China's oil shale are mainly sapropelitic (Ⅰ) and humosapropelic type (Ⅱ1)，secondarily, sapropelic-humic type (Ⅱ2)

H/C

rat

io

O/C ratio

Hyd

roge

n in

dex

Oxygen index



3. Maturity of Organic matter

Sample areas Province Ro(%)

Types of organic matter

Tmax（℃）

Dalianhe HeilongjiangJilin

LiaoningGuangdong

ShanxiXinjiang

0.46 II2 423Luozigou 0.48 I-II1 437Fushun 0.49 I 443

Maoming 0.51 I-II1 428Tongchuan 0.51 II2 432Sangonghe 0.51 II1 435

Ro of oil shale is 0.41%～0.60%, and Tmax is 423～446℃, so China's oil shale is mostly at immature-low mature stage of thermal evolution



Quality characteristics

1. Oil yield

Oil yield is the most important parameter of oil shale evaluation. In 2006, “National evaluation of oil shale resources in China” established that the boundary of oil yield is higher than 3.5%, it can be divided into three classes of low, middle and high : 3.5%＜ω≤5%, 5%＜ω≤10% and ω＞10%.

Shale oil resources whose oil yield in weight is higher than 5% takes up 67.64% of the total shale oil resources of the country, so the quality of China's oil shale is middle in general.


Nongan Luozigou

Fushun Denglouku

When oil yield in weight is higher than 3.5%, the content of organic carbon is usually higher than 6%. So the content of organic carbon could become one of indicators for helping judging oil shale.

Quality characteristicsCharacteristics of continental oil shale

2. Ash content

Ash content is the key indicator that distinguishes oil shale and coal. Generally, the ash content of oil shale is ＞40%

The ash contents of oil shale in main petroliferous shale areas in China are between 53.27% and 84.35%. By statistics the data of 54 petroliferous shale areas in China, the ash content of China's oil shale could be divided into two classes:

Low ash content: ash content is ＜65%, oil yield is ＞10%

High ash content: ash content is 65～90%，oil yield is 3.5～10%.

Thus，China's oil shale mostly belongs to high ash content oil shale.


3. Caloric value

Caloric value is an important parameter for evaluating the industrial fuels.

Caloric values of China's oil shale in each area are very different, Caloric value of Nongàn oil shale in Jilin Province is the lowest and is 4.19MJ/kg, and the caloric value of Ao`cheng oil shale in Jiangxi Province is the highest and is 34.60MJ/kg.

Thus oil shale with high caloric value can be directly used to generate electricity, and the ash after retorting can also be used for electric generation, which is a good way for comprehensive utilization of oil shale.






Mineralization model ofoil shale bearing basin

Oil shale in China is mostly deposited in continental environments, and concentrates in depression lake basins and fault deep lake basins.

545.2

84.2

0

100

200

300

400

500

600

Depression deep lake fault deep lake

Taking up 76％ of the

country

Taking up 12％ of the

country

Billion tons


Oil shale mainly deposited in

the 1st member of Qingshankou

Formation and the 1st and 2nd

member of Nenjiang Formation

of Upper Cretaceous.U

pper C

retaceous

Yaojia

Nenjiang

Qingshankou

（1）Strata characteristics

1.Depression deep lake basin—Songliao Basin

Songliao basin is a large scale depression basin during the period of oil shale deposition. The 1st member of Qingshankou and 2nd of Nenjiang Formation develop in Post-rift thermo-subsidence supersequence set

(2) Tectonic background



Yao5 Yao6 Yao9 Hai7 Qsh10

QingShan

Kou

(3) Sedimentary environment


Base-level change curve of Songliaobasin corresponds to sea-level change curve of the world.

Oil shale is the product of the two lake flooding periods

The 1st member of Qingshankou Formation: Upper AldanianThe 1st and 2nd member of Nenjiang Formation : Turonian


① Sea transgresstion

Sr/Ba curve of Songnan 15

Sr/Ba curve of Wan3



Perhaps exist transgression in K2qn1and K2n2

Evidence 1: Sr/Ba ratio

Qingshankou Formation: Pelecypoda fossil, fishbone, et.Nenjiang Formation: Pelecypoda fossil.1st member of Nenjiang Formation: Jilinichthys, Hama,

teeth fossil of shark, coral fossil and foraminifer fossil (GaoRuiqi, 1985; Ye Dequan, 1985).

Evidence 2:

Ta212 well, coral fossil , Qingshankou FormationTa212 well, coral fossil , Qingshankou Formation

Ta212 well, foraminifer fossil, Qingshankou Formation

Ta212 well, foraminifer fossil, Qingshankou Formation



Marine fossils

The two times of flooding and transgression caused

Songliao basin to have an anoxic environment. The

formation of black shale (oil shale ) is usually related to

anoxic environments; anaerobic conditions are

favorable for the conservation of organic matter, so

there formed three sets of black shale, mudstone and

oil shale

② anoxic environment





Evidence 1: Stratification of lake water

Sea transgression causes a kind of salintystratification, which makes the bottom of the lake an anoxic environment



Evidence 2: V/V+Ni ratioMicrogram/gram

Sample place Nongàn Hei100 Songyan10 Songyan9 Songyan4

Well number yyy7 yyy39 yyy108 yyy105 Songyan4

V 76.80 90.00 114.00 115.55 103.16

Co 12.70 27.40 19.84 12.77 13.10

Ni 46.70 51.50 32.06 27.94 31.57

Mo 5.01 2.93 8.04 5.27 3.70

Zn 100.00 216.00 97.58 83.95 75.86

Sr 87.00 142.00 340.00 180.00 140.00

Ba 289.00 196.00 290.00 410.00 370.00

Sr/Ba 0.30104 0.72449 1.17241 0.43902 0.37838

V/V+Ni 0.62186 0.63604 0.78053 0.80526 0.76569

Oil shale deposits in anoxic and fresh lake sedimentary

＜ 1＞0.5

Thickness contour of K1qn1 Thickness contour of K1n2

Oil yield and thickness of oil shale increase in the direction of Songliao basin subsidence


lithofaciespaleographic map

Qnsh Formation


(4) Depression deep lake oil shale (fresh water)

Oil shale mainly develop in Transgressive System Tract (TST) and Highstand System Tract (HST). Usually the deeper the water, the higher the oil yield and the greater the thickness, as typically represented in the Mesozoic Songliao, Junggar and Ordos basins.



Oil shale of Qingshankou Fomation in Nongànpetroliferous area（Qingshankou exploration area）

In TST，the times of lake-level and sedimentary cycles controls the layer numbers of oil shale. There is a sedimentary overlap in the direction of the basin, and shows regressive sedimentary

2. Fault deep lake basin (1) sequence characteristics

LST

TST

HST

RST

Pyrite

Oil shale

Oil shale

GongliangtouDachengziBeitaizi

北台子勘

查区大城子勘查区公郎头勘查区

南部勘查区

Huadian Basin

MFS

IFS13 layer recoverable oil shale

Thickness isoline of Huadian basin

Oil yield isoline of Huadian basin

(2) Fault deep lake oil shale (fresh or brackish)

Oil shale also develops in TST and HST, but the thickness and oil yield is obviously controlled by synsdimentary faulting, becoming thicker and richer in the direction of the fault, such as in Cenozoic Huadian, Fushun and Maoming Basins.







From 2004 to 2006, Jilin University developed “first national oil shale evaluation ”in China. Results show that oil shale resource in China is very abundant and widely distributed

Oil shale resources in China Oil shale resources in China

Oil shale resources of China are estimated as 719.9 billion tons, i.e., 47.6 billion tons of in-place recoverable shale oil. The recoverable resources of conventional hydrocarbon are 12 billion tons after deducing the loss of oil shale development and carbonization

20 Provinces47 basins

80 petroliferous shale area

Evaluation results in different areas of China

Oil shale is mainly distributed in eastern China, Central China and Qinghai-Tibet Area

16.8

4.3

9.8

2.4

7.3

2 1.1 0.5

12.7

2.8

02468

101214161820

Easternarea

Centralarea

Westernarea

Southernarea

Qinghai-Tibet area

Billion tons Eastern area takes up

35％ of the country

Shale oil resource

Recoverable Shale oil resource

Mainly distributed in Songliao, Ordos, Lunpola and Junggar Basin

Evaluation results in different basins

15.4

9.68.7

5.54

1.6 1 0.4 0.2 0.202468

10121416

SongliaoOrdosLunpolaJunggarQiangtangChaidamuMaomingDayangshuFushunSichuan

Shale oil resource

(32％)

(20％)(18％)

(12％)

Billion tons

Evaluation results in different strata

Oil shale in China ranges in age widely and is most concentrated in Mesozoic strata.

10.5

2.7

31.7

7.85.5

1.5

0

5

10

15

20

25

30

35

Cenozoic Mesozoic Upper Palaozoic

Shale oil resources Recoverable shale oil resources

Taking up 67％of the country

Billion tons

Controlled by dynamic systems of Paleo-Asiatic Ocean, Tethys－Paleo-Pacific and Indian－Pacific Ocean，the age of oil shale formation is gradually younger from Northwest to Southeast.

Distribution of oil shale

bearing basins

（Based on Jishun Ren，2005）

Fushun oil shale mine（biggest producing base in China）Established in 1928. In 1959, production per year was 720,000 tons, constituting more than 50% of the country’s production. In 2007, production of shale oil per year was 310,000 tons.

Oil shale resources in China Development of China`s oil shale

The mine is planning to produce 710,000 tons in 2010.

Biggest opencast mine in Asia

1. The oil yield of China's oil shale is mainly middle rank, and most are high-ash oil shale. The caloric values are different in each area; the type of organic matter of oil shale concentrate in Sapropelific (Ⅰ) and humic-sapropelic (Ⅱ1)type.

2. China's oil shale is concentrated in continental environments, and could be divided into depression deep lake type and fault deep lake type. The water characters that oil shale formed in are fresh and brackish, and oil shale usually forms in anoxic environments.

3. Oil shale resources in China are abundant, widely distributed in 20 provinces, 47 basins and 80 petroliferous shale area. Oil shale resources are estimated as 719.9 billion tons and the recoverable shale oil resources are estimated as 12 billion tons.

Conclusions

Conditions of oil shale formation

The favorable conditions for oil shale formation are as follows:

1. anaerobic environmentGenerally, anaerobic lakes are favorable environments for oil shale formation, which aid in the preservation of organic matter

2. Salinity condition of lake waterFresh and salty environments can both form oil shale, but lakes with high pH value could have higher production and dissolve more phosphorus, and phosphorus is one of main nutrients of initial productivity of lakes


2、Huadian Oil Shale Mine

At present, the production of shale oil in Huadian is more than 70,000 tons.

Now Fuxin Mining Group and Chengda Group is investing to develop Huadian oil shale, and planning to produce 300,000 tons oil shale


3、Luozigou Oil Shale Mine

Development began in 1958;

In 2007, the production of shale oil per year is 30,000 tons


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Characteristics of continental oil shale and oil shale resources

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